Element concentrations in tissues reveal spatial structure of Atlantic walrus management stocks

Abstract Ensuring harvested animal populations are managed at appropriate scales requires an understanding of underlying genetic and ecological structure (e.g., distribution). Element concentrations in animal tissues reflect environmental conditions and therefore provide proxy distribution data that can be used to define spatially discrete management units, or stocks. Using element analysis of blubber ( n = 89) and muscle samples ( n = 83), we investigated the spatial structure of the Foxe Basin (FB) and Hudson Bay‐Davis Strait (HB‐DS) Atlantic walrus ( Odobenus rosmarus rosmarus ) management stocks in Canada's central Arctic. Multivariate analysis of 34 essential and non‐essential element concentrations revealed differentiation between the FB and HB‐DS stocks, in agreement with current stock definitions. However, our analysis also revealed differentiation within the HB‐DS stock, between walruses collected near southeast Baffin Island and those sampled around Southampton Island in northern Hudson Bay. Spatially distinct components within the HB‐DS stock may be subjected to differential harvest pressures, and further assessment of stock substructure is recommended to avoid potential negative management outcomes.